Confirmed wrote

Controller: 192.168.100.0 subnet, VLAN 10 connected to an untagged port on VLAN 10 on the switch (can't change this or it will lose communication with the EAPs it is controlling

EAPs (x7): 192.168.100.0 subnet, management VLAN10.

ER7206 current: 192.168.0.0 subnet, VLAN1 

ER7206 desired: 192.168.100.0 subnet, VLAN10

Hi, the omada router works in VLAN1 by default and it's not allowed to be changed, you may refer to the guide below.

How to add an Omada Gateway to the network? (Controller 4.4.3 or above): https://www.tp-link.com/en/support/faq/3148/

How to configure Management VLAN in Omada SDN Controller (4.4.4 or above): https://www.tp-link.com/en/support/faq/2814/

I haven't try it but guess you need to adopt the new ER7206 in VLAN1 first, then configure Wired Networks with VLAN Interface and switch the OC200 into the VLAN10 network. OC200 may lose the communication with the switch/EAPs during the setup, but it should recover once the OC200 is back to VLAN10, you don't need to reconfigure them. So here are my suggestions:

1. If the OC200 is set with a static IP, change it to DHCP first, then disconnect the existing router from your network.

2. Plug the new ER7206 to the OC200 directly in default VLAN1 network, follow the above faq/3148/ to adopt the ER7206.

3. After adoption, configure the Wired Networks and put the OC200 back into the VLAN10 network.

4. If the ER7206 router is lost, use Omada discovery utility to inform the router where the controller is as per Step5 in faq/2814/.

Hope it helps.

  @Yannie Thanks for trying to help, but I'd already followed all of the faqs you've referenced below, and it still didn't work. I did resolve this by re-doing the whole process I'd already done three times before for some reason it worked (factory reset ER7206, assign Omada controller IP in standalone mode, move to switch with Er7206 on trunk port and OC200 on management VLAN, adopt, force provision, reboot ER7206). Worth noting too that the Omada Discovery Utility doesn't appear to work on Windows 11.

The question remains though - why is it not possible to change the default LAN? Especially given that it is not possible to set port PVIDs on the router in controller mode - all PVIDs are fixed at VLAN1 which is really not helpful.

Now of course I have the perennial and widely-reported problem of DHCP reservations not applying to LAN clients, and not being able to see all wired LAN clients on the OC200 interface. But one problem at a time I guess! Closely watching forum posts already made elsewhere.